Worldwide developments of high-speed communication system preferably used for transport means such as automobiles, airplanes, trains and shipping are now underway. For example, “MOST®” (Media Oriented System Transport) has been proposed as an optical communication standard in Europe.
FIG. 18 shows a conventional optical connector designed under the “MOST®” standard (“TYCO Electronics & MOST” in Presentations by MOST members on “All Members Meeting Apr. 3, 2001”). This connector is composed of an optical receptacle 1P built in an electronic equipment such as CD, DVD, GPS that can be used in the transport means, and an optical plug 2P for supporting a pair of plastic optical fibers (POF) 100. For example, when the optical plug 2 is connected to the optical receptacle 1, a data communication between the electronic equipment and a data base connected through the optical fibers becomes available in the transport means.
The optical receptacle 1 can be mounted on a circuit board in the electronic equipment, and is mainly composed of a pair of photoelectric conversion modules 10P having the capability of making photoelectric conversion between light signals transmitted through the optical fibers 100 and electrical signals used in the electronic equipment, a shield case 50P made of a metal material for accommodating the photoelectric conversion modules, a pair of optical couplers 200 such as optical-fiber members having a required length, each of which is placed between an optical device of the photoelectric conversion module 10P and an end of the optical fiber 100 supported by the optical plug 2P, optical-fiber housing 80 for accommodating these optical couplers therein, and a receptacle housing 40P for providing a space for making the connection between the optical plug 2P and the optical coupler 200.
One of the photoelectric conversion modules 10P has the capability of converting the optical signals transmitted through the optical fiber 100 to the electric signals, and the other one has the capability of converting the electric signals provided from the electronic equipment to the optical signals to be supplied to the optical fiber. As shown in FIG. 19, each of the photoelectric conversion modules 10P is provided with an optical device 12P such as light-emitting diode and light-receiving diode, and an electric circuit 14P electrically connected to the optical device by a lead wire 16P. After the optical device 12P and the electric circuit 14P are mounted on a single lead frame 90, they are integrally molded with a translucent resin 11P to obtain a resin molded article 95 having a substantially rectangular solid shape. When the optical plug 2P is connected to the optical receptacle 1P, the optical signals provided from the optical fibers 100 of the optical plug are transmitted to the optical devices 12P of the photoelectric conversion modules 10P through the optical couplers 200.
In addition, Japanese Patent Early Publication [kokai] No. 2001-13367 discloses an optical receptacle, as shown in FIG. 20. This optical receptacle is provided with a receptacle housing 40E having a front opening 41E, into which an optical plug (not shown) can be fitted, optical device modules 10E, a pair of sleeves 85 that are useful to improve production efficiency of the optical receptacle, and a cap 50E. The receptacle housing also has a rear opening 43E, through which the optical device modules 10E and the sleeves 85 are accommodated in the receptacle housing 40E.
The optical device modules 10E and the sleeves 85 are placed in the receptacle housing 40E such that when the optical plug is connected to the optical receptacle 1E, each of the top ends of the optical fibers supported by the optical plug is positioned in an opposing relation with the corresponding optical device module 10E through the sleeve 85. The sleeve 85 is composed of an optical waveguide portion made of glass or synthetic resin, and a cylindrical holder portion made of a metal material. Alternatively, an additional optical fiber having a required length may be used as the sleeve 85.
According to this optical receptacle, since the optical device module 10E is smoothly fitted in the receptacle housing 40E by use of the sleeve 85, it is possible to prevent the optical device module 10E from being inserted in an oblique direction into the receptacle housing, and also from a breakage caused by an accidental interference with the receptacle housing. Therefore, there is an advantage that production efficiency and yield of the optical receptacle are improved, as compared with conventional cases.
However, in the conventional optical receptacles described above, since the optical couplers 200 such as the optical-fiber members having the required length or the sleeves 85 are disposed between the top ends of the optical fibers supported by the optical plug and the optical devices of the optical receptacle, an increase in transmission loss of the optical signals comes into a problem. In addition, there is another problem of increasing total component counts of the optical receptacle.